Saffo: I doubt jetpacks will ever become commonplace for ordinary travel, though jet-powered devices (more likely micro-wings than jetpacks) will become popular if slightly esoteric sports devices. To get an idea of where this is headed, take a look at the strap-on wing that Felix Baumgartner used to cross the English Channel in 2003 (www.felixbaumgartner.com ). This first wing was just a gliding wing, but he and others (especially the military) are hard at work prototyping powered versions. It is rumored that the U.K. military is already using powered wings for secret operations. Just as the Rogallo wing originally developed by NASA to land space capsules turned into hang gliding, it is a safe bet that these strap-on wings will grow into some very interesting extreme sports.
Now, about not walking, the problem is with us today with automobiles. When the Segway was introduced a few years back, people were worried that it too would further reduce exercise. So your fear is very real, but let's hope people are sensible about knowing when to walk. Just as various health agencies advertise to take the stairs instead of the elevator/escalator today, perhaps we will see public service ads reminding us to use our feet more!
Q: Will personal communications devices reshape how we vote? Could we possibly vote with a text message?
Saffo: Great question! Imagine a future when informal polls conducted by personal devices (phones, PDAs, etc) actually reflect in absolute numbers a larger portion of the population than formal votes do. We would be in a strange world where public opinion could be quantified and empirically demonstrated to be different and more accurate than actual voting. This, of course, would create all sorts of problems.
Now, about conducting an actual formal vote by cell phone, it is technically plausible. After all, one can use one's phone in places like Finland to buy gasoline and in Japan to buy all sorts of items. If a system is reliable enough to allow people to part with their money, it is reliable enough to vote on. In fact, compare the reliability of ATM machines to voting machines. ATM machines are extraordinarily reliable. Voting by phone or some other existing system has another advantage; if the system used to vote is a system used every day, then both the supervisors and the public will have a higher confidence level in its accuracy compared to a system that is used only once every two years.
So it is practical and appealing compared to current systems. But will it happen? I doubt it because of the entrenched interests in Washington and among the voting machine makers who will do everything to avoid a change.
Q: Do you have any theories on how the world will end? Meteorite? Drought? Nuclear attack?